pls explain this info

I dont understand what they are trying to say

http://www.medpagetoday.com/Urology/ProstateCancer/14990

This is about a re-analysis of a previous cancer prevention study.

In the original study, healthy men took the drug finasteride for seven years. These men had 25% fewer cases of PC when compared to men who took a placebo. BUT the men taking finasteride who were diagnosed with PC were more likely to have high-grade PC when compared to the men in the placebo group who were diagnosed with cancer. This raised a serious concern that, while taking finasteride might reduce a man’s chances of getting PC, it increased the chance that if a man taking finasteride did get cancer, it would be more likely to be high-grade.

The follow-up study reported here concluded that finasteride made high-grade cancer easier to diagnose because it shrank the prostate and this made PSA tests more accurate. Thus it was not that the men taking finasteride had more high-grade cancer but that their high-grade cancers were more likely to be diagnosed compared to high-grade cancers in men not taking finasteride.